The international scientific community has reached consensus that ongoing climate change has raised the earth's global average temperature, has had an effect on the earth's ecosystems, and that larger impacts are likely in the future (IPCC AR4 2007). Current and future effects may include an increase in sea level, a reduction in the percentage of the earth's surface covered by the polar ice caps, changes in rainfall distribution and increases in the severity of storms. These changes may in future lead to effects on the oceanic currents and further changes in weather patterns, that could in turn lead to effects as diverse and profound as changes in the distribution of habitable land areas for various species, as well as in the distribution of areas suited to agriculture, and changes in locations of usable coastal ports and shipping routes. A positive feedback loop known as the Ice-Albedo Feedback Effect is involved in the reduction of icecap area, whereby the more the ice melts, the faster the remaining ice melts. This occurs because for a given area, the open ocean absorbs more solar energy (has a lower albedo) than does ice.
Weather patterns may be shifting as a result of climate change. Such changes may include changes in droughts, tropical storm strength and intensity, ocean currents, and wildfires.
Various solutions and geoengineering approaches to mitigate to some climate change effects have been proposed. The most commonly proposed long-term solution is to slow down the effects of global warming by addressing one apparent cause of global warming via a reduction in the generation of anthropogenic greenhouse gases such as carbon dioxide (CO2). The international scientific community agrees that the concentration of CO2 in the atmosphere has increased as a result of human activity and that this has caused an increase of the earth's global average temperature over the past several decades (IPCC AR4 2007).
Many proposals for reduction of the generation of greenhouse gases include proposals to reduce the rate of CO2 generation. For example, CO2 generation may be slowed down by providing for energy and transportation needs through the use of alternative power generation such as solar, wind, hydroelectric and nuclear power, and the use of alternative transportation fuels, such as electricity and various forms of bio-derived liquid fuels. These proposals and others like them are likely an important part of the long-term solution to reducing a man-made increase in CO2, but they could take decades to implement widely, and there are substantial technological, sociological, political and economic hurdles to be overcome before widespread adoption is likely to occur.
Another type of proposed solution is aimed at conducting geoengineering directed toward mitigating some of the effects of global warming. One example of such a proposal is the addition of specific gases to the atmosphere to produce an “anti-greenhouse” effect. Some sulfur-containing industrial pollutants have been shown to have a negative greenhouse effect, leading this idea's proponents to advocate a deliberate increase in these pollutants.
Another proposal to reduce the effects of global warming is to use orbiting solar reflectors. For example, it is proposed that trillions of mirrors be sent up into earth orbit to reflect some percentage of incoming sunshine.
Some parties have suggested carbon sequestration to reduce global warming. Various plans include burying carbon compounds in the ground, and seeding the oceans with iron to increase phytoplankton colonies, with the hope that as the plankton die, the carbon they've incorporated will sink to the ocean bottom.
In another proposal, floating plastic islands may be used to limit global warming. The idea includes covering part of the ocean with a material that has reduced absorption of solar energy and has a higher albedo.
Some difficulties with the methods listed above include their cost, irreversibility (for instance, if the solution overcorrects), the massive public works nature of the solutions, unintended weapons potential, and possible severe secondary problems (such as acid rain or health effects from added atmospheric sulfur compounds). Some negative effects of these proposals may include uncontrolled change in oceanic evaporation rate and change to the local ecosystem, ecological effects (such as a change in the plankton species selection), and unintended reverses of the solutions (such as sudden release of CO2 from sequestration schemes). It is thought this could occur if the temperature of the earth (and/or ocean) increases sufficiently over time to cause a release of sequestered CO2.
There is a need for improved systems and methods of environmental modification that may be applied locally and that may be fully reversible or may be used to correct environmental effects in the opposite direction until the desired stabilization is achieved.